Personal video recorders (PVRs), e.g., TiVo and ReplayTV devices, offer a variety of conveniences to users who record and store programming content. For example, these devices enable a user to record programs without having to set a timer, and to store the content without having to insert and set up any such recording medium as a videotape or disk. The recorded programming content can be viewed by the user with functions including: reverse, fast-forward, pause, index, fast/slow play and fast/slow reverse play.
Examples of prior art PVRs are described in U.S. Pat. No. 5,371,551 issued to Logan et al. (the '551 patent), U.S. Pat. No. 6,233,389 issued to Barton et al. (the '389 patent) and U.S. Pat. No. 6,324,338 (the '338 patent) issued to Wood et al. The '551 patent describes a PVR device employing a “circular buffer” which constantly records one or more incoming audio or video programs. Incoming analog broadcast programs are digitized and compressed prior to storage in the buffer, then decompressed and converted back into analog form for playback.
The '389 patent describes a PVR device which allows a user to store selected television broadcast programs while the user is watching or reviewing another program. The program data is compressed pursuant to an MPEG standard and separated into video and audio components for storage.
The '338 patent describes a PVR device having integrated channel guides allowing a user to control recording and storage of television programs into personal channels for later playback and viewing.
A concern common to the prior art PVR designs described above is management of limited storage space for storing desired programming content. A well known solution is to rely on a data compression scheme, e.g., the aforementioned MPEG scheme to compress program data before its storage to effectively utilize the limited storage space. In the event that the storage overflows, the '338 patent suggests that preexisting stored programs be deleted based on their predetermined priority to make room for new programs.